bug#25875: 26.0.50; Hang logging out of MS-Windows

[Ken Brown <kbrown@cornell.edu>]

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On 2/27/2017 3:14 AM, Richard Copley wrote:
> Sorry Ken, I can't sabotage myself like that, I have work to do.

FWIW, I'm attaching a corrected version of the patch.  With one 
exception, it only replaces SendMessage by SendMessageTimeout in cases 
where the return value of SendMessage was not used.  In the exceptional 
case, the return value was only tested to see if it was 0 or not, so I 
think the replacement is still correct.

Richard, it's your call whether or not it's worthwhile for you to run 
with this patch for a while and see what happens.  I understand that 
this might not give a definitive answer.

I still want to eventually apply the patch I posted in 
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=25875#41, which I think 
will solve the problem in a less satisfactory way.  But I'd rather hold 
off on that in the hope that we'll get some evidence as to whether we've 
correctly diagnosed the problem.

Ken

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diff --git a/src/w32term.c b/src/w32term.c
index d6b78fd..ba646fb 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -548,7 +548,8 @@ x_update_window_begin (struct window *w)
   /* Hide the system caret during an update.  */
   if (w32_use_visible_system_caret && w32_system_caret_hwnd)
     {
-      SendMessage (w32_system_caret_hwnd, WM_EMACS_HIDE_CARET, 0, 0);
+      SendMessageTimeout (w32_system_caret_hwnd, WM_EMACS_HIDE_CARET, 0, 0,
+			  0, 100, NULL);
     }
 
   w->output_cursor = w->cursor;
@@ -714,7 +715,8 @@ x_update_window_end (struct window *w, bool cursor_on_p,
      x_update_window_begin.  */
   if (w32_use_visible_system_caret && w32_system_caret_hwnd)
     {
-      SendMessage (w32_system_caret_hwnd, WM_EMACS_SHOW_CARET, 0, 0);
+      SendMessageTimeout (w32_system_caret_hwnd, WM_EMACS_SHOW_CARET, 0, 0,
+			  0, 100, NULL);
     }
 }
 
@@ -3668,8 +3670,8 @@ static BOOL
 my_show_window (struct frame *f, HWND hwnd, int how)
 {
 #ifndef ATTACH_THREADS
-  return SendMessage (FRAME_W32_WINDOW (f), WM_EMACS_SHOWWINDOW,
-		      (WPARAM) hwnd, (LPARAM) how);
+  return SendMessageTimeout (FRAME_W32_WINDOW (f), WM_EMACS_SHOWWINDOW,
+			     (WPARAM) hwnd, (LPARAM) how, 0, 100, NULL);
 #else
   return ShowWindow (hwnd, how);
 #endif
@@ -3687,7 +3689,8 @@ my_set_window_pos (HWND hwnd, HWND hwndAfter,
   pos.cx = cx;
   pos.cy = cy;
   pos.flags = flags;
-  SendMessage (hwnd, WM_EMACS_SETWINDOWPOS, (WPARAM) &pos, 0);
+  SendMessageTimeout (hwnd, WM_EMACS_SETWINDOWPOS, (WPARAM) &pos, 0,
+		      0, 100, NULL);
 #else
   SetWindowPos (hwnd, hwndAfter, x, y, cx, cy, flags);
 #endif
@@ -3697,29 +3700,31 @@ my_set_window_pos (HWND hwnd, HWND hwndAfter,
 static void
 my_set_focus (struct frame * f, HWND hwnd)
 {
-  SendMessage (FRAME_W32_WINDOW (f), WM_EMACS_SETFOCUS,
-	       (WPARAM) hwnd, 0);
+  SendMessageTimeout (FRAME_W32_WINDOW (f), WM_EMACS_SETFOCUS,
+		      (WPARAM) hwnd, 0, 0, 100, NULL);
 }
 #endif
 
 static void
 my_set_foreground_window (HWND hwnd)
 {
-  SendMessage (hwnd, WM_EMACS_SETFOREGROUND, (WPARAM) hwnd, 0);
+  SendMessageTimeout (hwnd, WM_EMACS_SETFOREGROUND, (WPARAM) hwnd, 0,
+		      0, 100, NULL);
 }
 
 
 static void
 my_destroy_window (struct frame * f, HWND hwnd)
 {
-  SendMessage (FRAME_W32_WINDOW (f), WM_EMACS_DESTROYWINDOW,
-	       (WPARAM) hwnd, 0);
+  SendMessageTimeout (FRAME_W32_WINDOW (f), WM_EMACS_DESTROYWINDOW,
+		      (WPARAM) hwnd, 0, 0, 100, NULL);
 }
 
 static void
 my_bring_window_to_top (HWND hwnd)
 {
-  SendMessage (hwnd, WM_EMACS_BRINGTOTOP, (WPARAM) hwnd, 0);
+  SendMessageTimeout (hwnd, WM_EMACS_BRINGTOTOP, (WPARAM) hwnd, 0,
+		      0, 100, NULL);
 }
 
 /* Create a scroll bar and return the scroll bar vector for it.  W is
@@ -6538,7 +6543,8 @@ x_iconify_frame (struct frame *f)
   x_set_bitmap_icon (f);
 
   /* Simulate the user minimizing the frame.  */
-  SendMessage (FRAME_W32_WINDOW (f), WM_SYSCOMMAND, SC_MINIMIZE, 0);
+  SendMessageTimeout (FRAME_W32_WINDOW (f), WM_SYSCOMMAND, SC_MINIMIZE, 0,
+		      0, 100, NULL);
 
   SET_FRAME_VISIBLE (f, 0);
   SET_FRAME_ICONIFIED (f, true);